Turbine-bucket construction.



E. W. RICE, JR. TURBINEBUGKETCONSTRUCTION.

APPLICATION FILED JUNE 28, 1909.

Patented Jan.3,191 1-.

Inventor-z Edwin WRiceJr-. DH J oqtt'g.

Witne sses:. m w

unrrnn stapes; rant EDWIN w. RICE, an, or scnnnncranr, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A conrona'rron or NEW roan.

TURBINE-BUCKET CONSTBU'JTION.

Specification of Letters Patent.

Application filed June 28, 1909.

Patented Jan. 3, rear.

Serial No. 504,639.

To allwhom it may concern:

Be it known that I, EDWIN W. RICE, Jr.,

a citizen of the United States, residing at.

Schenectady, county of'Schenectady, State of New York, have invented certain new and cover or shroud to the free ends of the buckets.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and Tlaims appended thereto.

In the accompanying drawing which is illustrative of my invention, Figure 1 is a view in side elevation of a portion of a row of buckets either for a rotor or stator; Fig. 2 p is a plan view of a bucket; Fig. 3 is a section view of a bucket showing the-cover or shroud in place; Fig. 4 is a detail view showing the cover in section and a bucket in dotted lines; Fig. 5 shows a slight modification wherein the cover or shroud is secured by two means instead'of one; Fig. 6 is a side view of a cover or shroud and Fig. 7 is a bottom view of'the shroud or cover My invention is applicable to impulse and reaction turbines, and to a combination of both types, and this whether the buckets, blades or vanes are carried by disk-like wheels or drums. It is also applicable to stator as well as rotor buckets.

1 indicates the barrier or support for the buckets which may be stationary or rotary. It may be a disk, wheel, drum or casing or a part which is secured thereto. Mounted on the carrier are buckets or vanes2, .which may extend radially or axially depending upon the direction of flow of the steam or other motive fluid. The buckets or vanes may be secured at their roots by any suitable means. Mounted on the buckets or vanes is a cover or shroud 3 that is made in one or more pieces or sections, usuall in a number of relatively short lengths or convenience in manufacturing and assembling, especially where the buckets 01' vanes have a slanting top or end to provide for an enlargement of the spaces or working passages between said buckets or vanes. some good tough met-til and is relatively thin The cover is made of in order to make it as light as possible. The under side of the coveror shroud is rovided with pro ect1ons at usually one or each bucket. These projections may be formed in a variety of ways and for the purpose of strength are made integral with said cover but under certain conditions where the centrifugal stresses are moderate they may be separately made and 'afiixed to the cover. In either event they will form a part of the cover or shroud as distinguished from the buckets. Assuming that they are to be formed integral, a convenient method of manufacture is as follows: The cover is rolled or otherwise formed to the desired shape and size and on the under side is formed a ridge 5 of suitable depth and width to form" the finished projection 4. The portion of the ridge 5 between the pro!- jections may then be removed by a milling or other machine operation. I prefer to remove this metal in'order to'avoid forming a resistance or obstruction 'in the bucket space. The tops or free ends of the buckets are provided Wlth' grooves or recesses of such shape that when the metal forming the projecti us is upset,'expanded or caused to flow therdin under pressure, the projections will fill s id grooves or recesses and firmlyiunite the over and the'bucke'ts. As an example I may advantageously use dovetail slots or grooves 6. The under surface of each pro- JGCtlO may be so shaped orbeveled that when forced against the bottom wall of the groove it will tend to expand. Such an arrangement is shown at 7 Figs 4:. This 'shipe is or may be given to the entire ridge an it is found desirable to obviate an adiitional machine operation.

Iii assembling, the buckets-are first mounted in place. on the carrier, or for that matter they may be formed integral therewith. The cover or shroud is then mounted in position on the buckets with the projections registering with the dovetail grooves, slots, or recesses. Pressure is then applied to the cover directly over the projections 4: which causes their lower ends to expand and fill s'aid grooves or slots. This pressure ma be applied in a variety of ways depen 'ng upon the arrangement and character of the buckets. It may be done by a pneumatic hammer, or by pressure from a ram or other agency. Where the buckets are relatively thin thcymay be supported by clamps or i t Zia means are provided to prevent such tendens-y. As an illustration of this feature of my invention the projections are provided with extensions or pins 8 that enter correspondingl r'shaped holes 9 in the buckets. When the projections 4t are'inserted in the grooves 6 preparatory to expanding them the pins will enter the holes 9 and-the proper relation of the parts will be preserved not only during the expanding operation but when the machine is in service.

In accordance with the provisions of the patent statutes, I have described the principle'of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but it desire to have it understood that the apparatus shown is only illustrative and that the invention can be-carried out by other means.

li'liat I claim as new and desire to secure by Letters Patent of the United States, is

1. In a turbine, the combination'of a sup port, buckets mounted thereon and arranged in a row, said buckets having open-ended slots in their free ends, acover or shroud for the free ends of the buckets, means carried by the cover and engaging the slots for uniting-said cover with the buckets, and devices for preventing the buckets from moving relative to the cover in the plane of the row 2. In a turbine, the combma'tion of a sup port, buckets mounted thereon that have open-ended dovetail grooves in their free ends, a cover for the buckets havingintegral projectmns that enterthe grooves in the sauces buckets and are expanded therein to hold the cover in place, and devices for preventing the walls of the bucket grooves and the projections from being disengaged.

3. in combination, a plurality of turbine buckets having recessed outer ends, a support for the buckets, a cover or shroud for the free ends of the buckets, and projections on the under side of said cover which enter the recesses, the end of each projection being beveledfrom the edges toward its center to facilitate expanding when pressure is applied thereto.

i. In a turbine, the combination of a port, buckets mounted thereon that have open-ended dovetail grooves in their free ,ends, there being holes extending into the bodies of the buckets from the bottom of the grooves, a cover for the buckets having integral projections that enter said grooves and are expanded therein to hold the cover in place, and extensions on the projections -that enter said holes to prevent the walls of the bucket grooves and the projections from being disengaged.

5. In combination, a support, a bucket mounted thereon that has an open-ended groove in its free end and a hole extending lnto the body of the bucket from the bottom of the groove, a bucket cover having a pro jection which engages the grooveand is'-secured therein, and an extension on the proj ection that engages said hole.

6. In combination, a sup ort, a bucket mounted thereon, a cover fbr the bucket, and means for securing the cover to the bucket comprising a projection on one of said members engagingan open-ended slot in the free end of the other and an extension on the projection that enters a hole ex tending from the bottom of the slot.

In witness whereof, I have hereunto set my hand this 26th day of June, 1909.

EDWIN W. men, at.

Witnesses:

BENJAMIN B. HULL, HELEN Onronn. 

